Concentric foraminous shaping means for tubes or bars



Jam 17, 1967.

- E. F. MACKS CONCENTRIC FORAMINOUS SHAPING MEANS FOR TUBES OR BARSOriginal Filed Aug. 22. 1960 2 Sheets-Sheet 1 INVENTOR. ELMER, FREDMACKQ A fforneys CONCENTRIC FORAMINOUS SHAPING MEANS FOR TUBES OR BARSOriginal Filed Aug. 22,- 1960 E. F. MACKS Jan. 17, 1967 2 Sheets-Sheet 2Fig. 5

INVENTOR.

. A & 8 m s M W A; Mwm M fl M m 0/ R I W; C aw United States Patent CONCENTRIC FORAMINOUS SHAPING MEANS FOR TUBES 0R BARS Elmer Fred Macks,Willow Lane, Vermilion, Ohio 44089 Continuation of application Ser. No.353,016, Mar. 12,

1964, which is a continuation of application Ser. No. 50,939, Aug. 22,1960. This application May 11, 1965, Ser. No. 458,822

9 Claims. (Cl. 6525) This application is a continuation of applicationSer. No. 353,016, entitled Continuous Molding Apparatus, filed Mar. 12,1964, now abandoned in favor of this application, which originally was acontinuation of application Ser. No. 50,939, entitled Continuous MoldingApparatus, filed Aug. 22, 1960, also abandoned.

This invention pertains to a method anl apparatus for precision formingof molten substances and more particularly to a novel and improvedmethod and apparatus for precision molding of continuous shapes.

With this invention the material to be molded is disposed, While in amolten state, in a vessel. The vessel has an outlet port or gate throughwhich the material passes. An external die in the form of a foraminoustube is secured to the vessel and surrounds the port. The

foraminous tube receives material as it flows outof the port. The innerwalls are of the contour of the object to be molded.

During a molding operation gas'under pressure is passed through thewalls of the foramin-ous tube to generate a gas film around the objectbeing molded and between the object and the tube. The object ismaintained in spaced relationship with the tube by this gas film, andthe dimensions of the object can be controlled somewhat by adjusting thepressure of the gas film; thus a controlled taper may also be cyclicallyintroduced.

When hollow objects are to be molded, a foraminous mandrel shaped to thecontour of the inside surface of the object is provided. Gas underpressure is passed through the wall of the mandrel to form a gas filmbetween the object and mandrel to keep the object being i the film ofgas was not present as an insulating medium.

Accordingly, one of the principal objects of this invention is toprovide a novel and improved method of and apparatus for continuouslymolding elongated members of essentially uniform cross section.

Another object of this invention is to provide an improved continuousmolding method in which the dimensions of the object being molded may becontrolled by adjusting the pressure of gas in a film formed between theobject and foraminous dies defining the contour of the object beingmolded.

, -An additional object of this invention is to provide an improvedmethod of molding in which the pressure head of the molten material tobe molded is. used to force the material through the object shapingdies.

A related object is to provide a novel and improved apparatus formolding and method of using such apparatus in which the pressure head isadjusted by applying either suction or pressure to the surface of thematerial to be molded.

Expressed another way, another object is to provide "ice a pressurizedgas above the molten pool to control velocity of out flow and thusmaintain more uniform properties of finished product.

A further object of this invention is to provide a novel and improvedmethod of continuously casting metal in which an inert gas is used tomaintain the object being cast out of contact with the foraminousforming dies.

Another object of this invention is to provide an apparatus for moldingwith the described method in which the permeability of the walls of themolding dies increases from top to bottom to provide a film of gas ofessentially uniform thickness and pressure from top to bottom.

Still'another object is to provide a mechanism made in accordance withthe foregoing objects in which a valve is provided at the gate and inwhich at least one of the dies tapers to provide a funnel-like entranceto the molding region.

Another object is to provide a mechanism made in accordance with any ofthe preceding objects in which fluid forming the film separating theobject from the dies is introduced at a series of locations andtemperatures to control the rate of flow and the rate of hardening.

Other objects and a fuller understanding of the invention may be had byreferring to the following description and claims taken in conjunctionwith the accompanying drawings in which:

FIGURE 1 is a sectional view of the device in somewhat schematic formshowing glass as the object being molded and the valve closed;

FIGURE 2 is a foreshortened sectional view of the molding portion of themechanism with the valve in an open position and showing the moldingprocess in operation and also'showing slightly modified forming dies;

FIGURE 3 is a sectional view of the device as seen from the planeindicated by the line 33 of FIGURE 2;

FIGURE 4 is a sectional view of the device similar to the view of FIGURE3 and showing molding dies to shape an object of another configuration;and,

FIGURE 5 is a sectional view on an enlarged scale showing a mechanismwith a controlled rate of flow. and a controlled rate of solidification.

Referring now to the drawings and to FIGURE 1 in particular, a materialsupporting vessel is shown generally at 10. The vessel may includeheaters 11 to maintain in a molten state material 12 carried by thevessel. In the drawings the molten material 12 is glass, because themethod and apparatus of this invention is ideally suited for the shapingof glass bars and tubes, refractory metals, etc.

The vessel has a port or gate 15 preferably at the base thereof. When anobject is not being molded, the gate 15 is closed by a valve 16. Thevalve 16 is shiftable from the closed position of FIGURE 2 by actuationof a suitable control means such as lift bars 17. This valve 16 may beeliminated where the process is continuous.

- An exterior forming die in the form of a foraminous tube 18 isprovided. The tube has an inner surface -19 which is contoured to theshape of the object to be molded. The surface 19 may, of course, haveany of a wide variety of forms. As illustrative examples, the surface 19of FIGURE 3 is cylindrical while the surface 19 of FIG- URE 4 isoctagonal.

A housing 20 surrounds the tube 18 to' define a fluid chamber 21therebetween. A conduit 23 connects the chamber 20 to a source of fluidunder pressure 24. A control valve 25 is connected to the conduit 23.

When the object to be molded is hollow, a foraminous internal die ormandrel 27 isprovided. The mandrel 27 will normally be positionedconcentrically with respect to the surface 19 to provide a uniformmolding space 35 therebetween and, therefore, a finished object ofuniform cross section. Gas under pressure is supplied to a cham ber 28in the interior of the mandrel by a conduit 29. The conduit 29 isconnected to a source of gas under pressure 30. A valve 31 is connectedto the conduit 29 to control the flow of gas therethrough.

In FIGURE 2 the tube and mandrel each take a slightly modified form, andfor this reason they are designated by the numerals 18' and 27'respectively. The tube and mandrel flare inwardly in funnel-like fashionat 32 and 33 to a throat at 34. These inward flares are provided tofacilitate the flow of the material 12 into the molding region definedby the tube and mandrel.

The tube and mandrel 18' and 27' are modified in another respect. Thewall thickness of the two gradually increases from top to bottom toprovide permeability which also gradually decreases from top to bottom.With this mechanism the gas flowing through the foraminous walls willthereafter flow outwardly with the object being formed. Withpermeability that decreases from top to bottom, the gas flow through theforaminous walls will decrease from top to bottom. The decreasingpermeability tends to produce a gas suppont film of uniform thicknessand pressure between the walls and the object from top to bottom.

The tube and mandrel 18, 27 may be formed of sintered metal. The metalused will depend on the molding temperature encountered. Permeablestainless steel, for example, may be used for molding certain glassobjects. Dies of permeable ceramic such as aluminum oxide (A1 may beused for high temperature melting materials such as bronzes, steels,etc.

In operation film support gas under pressure is first introduced intothe chambers 21, 28. This gas may be air. Molding may be accomplished inan inert atmosphere merely by employing an inert gas as the film supportfluid. If oxidization of the material is desired, the gas may containmore oxygen than air.

When gas under pressure is in the chambers and flowing through the walls18, 27, the valve 16 may be opened to allow the glass or other material12 to gravity flow out of the vessel 10 and through the gate 15. As willbe explained in greater detail in connection with FIGURE 4, the top ofthe vessel 10 may be sealed and pressurized or a vacuum drawn to controlthe velocity of flow.

A film of gas will form between the surface 19 and the elongated objectbeing formed. If the object is hollow, the mandrel 27 is present and asecond film will form between the mandrel 27 and the object. It isimportant the films be present at least as high in the molding region 35as the location where the material begins to solidify. The films mayform above this location, but if they only form below it, imperfectmolding will result.

The tube and mandrel are of suificient length so that the material isfully solidified before it passes out of the molding region 35. Asuitable cut-ofi mechanism, not shown, may be positioned immediatelybelow the region 35 to cut the finished objects to suitable lengths.Simi larly, a support mechanism, also not shown, may be provided if thedesired finished lengths are of such length that their weight affectsthe molding operation. Objects of specified length may be continuouslymolded merely by control of valve 16 in an open-close cycle ofpredetermined duration.

One of the outstanding advantages of this invention is that the sizetolerances of the finished object may be very simply and expeditiouslycontrolled within certain limits. If the thickness of the objects beingformed is too great, the pressure in the chambers 21, 28 and, therefore,in the films, may be increased. If the object thickness is too small,then one or both of the pressures may be decreased. If only the insideor the outside diameter of the object is incorrect, then only theappropriate one of the chamber pressures need be altered.

In FIGURE 5 the vessel is closed by a cover 40. Material may beintroduced into the vessel through conduit 41 when a control valve 42 isopen. A slag removal tap is provided at 39. The pressure in space 43above the molten material 12 is controlled by a pressure control means44. The pressure control means 44 may be either a suction or a pressuresource. The pressure control means is in communication with the space 43through a conduit 45. The pressure control means is regulated by a valve46. p

In FIGURE 5 the tubular die is designated by the numeral 47. The die 47is surrounded by a series of chambers 50, 51, 52, 53, which areseparated by baflles 54, 55, 56. The chambers 50, 51, 52, 53 aresupplied gas under pressure by conduits 60, 62, 63, 64, respectively.The conduits 60, 62, 63, 64 are supplied by sources P-1, P2, P3, P4,respectively, and controlled by valves V-l, V-2, V-3, V4. Thetemperature of the gas in these conduits may be controlled by suitablemeans T-1, T-2, T-3, T-4. Thus, both the rate of hardening and the rateof flow of the material being molded may be controlled.

While the invention has been described with a great deal of detail, itis believed that it essentially comprises a mechanism for moldingincluding a vessel having a gate, foraminous tubular die meanspositioned around and below the gate, and means to pass a fluid underpressure through the walls of the foraminous tube. The invention alsoincludes a method of using such a mechanism.

Although the invention has been described in its preferred form with acertain degree of particularity, it is understood that the presentdisclosure of the preferred form has been made only by way of exampleand that numerous changes in the details of construction and thecombination and arrangement of parts may be resorted to withoutdeparting from the spirit and the scope of the invention as hereinafterclaimed.

What is claimed is:

1. A molding apparatus comprising:

(a) a vessel for containing a quantity of molten material to be molded,said vessel having a gate opening in a lower portion thereof;

(b) a foraminous tube secured to the vessel and sur rounding and belowsaid opening to receive material passed through such opening;

(c) the tube defining a molding region and having an inner surface ofuniform cross section from one end of the region to the other, saiduniform cross section being of the contour of an object to be molded;

(d) a member surrounding the tube and defining a fluid chamber betweenthe member and the tube;

(e) means connected to the member to supply fluid under pressure to thechamber and cause fluid under pressure to flow through the foraminoustube;

(f) a foraminous mandrel having an internal fluid chamber suspended inthe tube in spaced relationship with said inner surface;

(g) the mandrel having an outer surface of uniform cross section fromone end of the molding region to the other of the contour of theinterior of a tubular object to be molded;

(h) the mandrel having an internal chamber;

(i) a fluid supply means connected to the mandrel to supply fluid underpressure to the mandrel chamber; and,

(j) means for controlling the pressure of the gas supplied by each ofsaid supply means and thereby control the dimension of an object beingmolded.

2. The device of claim 1 wherein the mandrel and tube are dies andwherein at least one of the dies has decreasing permeability from top tobottom.

3. The method of continuously molding an elongated object comprising:

(a) providing a quantity of molten material;

(b) shaping the material into an elongated member of constantcross-sectional configuration by continuously feeding the materialthrough a molding region with force applied by the molten material andthe region defined by a foraminous tube shaped to the contour of theobject being molded;

(c) solidifying the material as it moves through said region byconfining the material in the region until it solidifies to its finishedshape; and,

(d) maintaining a thin circumscribing film of moving gas around theentire object being molded from one end of the region to the other bycontinuously passing gas from a plurality of spaced sources of gas underpressure through the Walls of the foraminous tube.

4. The method of claim 3 wherein the temperature and pressure gradientsin the film are controlled by independently adjusting the temperatureand pressure of each ofthe gas sources.

5. The method of claim 3 wherein the rate of solidification of themember is controlled by independently controlling the temperature of thegas from each of said sources.

6. A molding apparatus comprising:

(a) a vessel for containing a quantity of molten material to be molded,said vessel having a gate opening in a lower portion thereof;

(b) a foraminous tube secured to the vessel and surrounding and belowsaid opening to receive material passed through such opening, the tubehaving inner and outer surfaces;

(c) the tube inner surface defining a molding region of uniform crosssection from one end of the region to the other, said uniform crosssection being of the contour of an object to be molded;

(d) means surrounding the tube and defining a plurality of fluidchambers adjacent the tube outer surface; and,

(e) a plurality of fluid supply means respectively connected to thechambers to supply fluid under pressure to the chamber and cause fluidunder pressure to flow through the foraminous tube.

7. The device of claim 6 wherein the means for con- (b) shaping thematerial into an elongated member of constant cross-sectionalconfiguration by continuously feeding the material through a moldingregion with force applied by the molten material with the region definedby a foraminous tube shaped to the contour of the object being molded;

(c) solidifying the material as it moves through said region byconfining the material in the region until it solidifies to its finishedshape;

(d) maintaining a thin circumscribing film of moving gas around theentire object being molded from one end of the region to the other bycontinuously passing gas under pressure through the Walls of theforaminous tube;

(e) maintaining the object in the region until it has solidified to itsfinished shape; and,

(f) controlling the thickness of the member by adjusting the pressure ofthe gas passed under pressure through the Walls of the foraminous tube.

References Cited by the Examiner UNITED STATES PATENTS 1,653,848 12/1927Grotta -86 1,750,971 3/1930 Soubier 65-86 2,444,731 7/ 1948 Devol 65-252,478,090 8/1949 Devol 65-25 DONALL H. SYLVESTER, Primary Examiner.

F. W. MIGA, Assistant Examiner.

1. A MOLDING APPARATUS COMPRISING: (A) A VESSEL FOR CONTAINING AQUANTITY OF MOLTEN MATERIAL TO BE MOLDED, SAID VESSEL HAVING A GATEOPENING IN A LOWER PORTION THEREOF; (B) A FORAMINOUS TUBE SECURED TO THEVESSEL AND SURROUNDING AND BELOW SAID OPENING TO RECEIVE MATERIAL PASSEDTHROUGH SUCH OPENING; (C) THE TUBE DEFINING A MOLDING REGION AND HAVINGAN INNER SURFACE OF UNIFORM CROSS SECTION FROM ONE END OF THE REGION TOTHE OTHER, SAID UNIFORM CROSS SECTION BEING OF THE CONTOUR OF AN OBJECTTO BE MOLDED; (D) A MEMBER SURROUNDING THE TUBE AND DEFINING A FLUIDCHAMBER BETWEEN THE MEMBER AND THE TUBE; (E) MEANS CONNECTED TO THEMEMBER TO SUPPLY FLUID UNDER PRESSURE TO THE CHAMBER AND CAUSE FLUIDUNDER PRESSURE TO FLOW THROUGH THE FORAMINOUS TUBE; (F) A FORAMINOUSMANDREL HAVING AN INTERNAL FLUID CHAMBER SUSPENDED IN THE TUBE IN SPACEDRELATIONSHIP WITH SAID INNER SURFACE; (G) THE MANDREL HAVING AN OUTERSURFACE OF UNIFORM CROSS SECTION FROM ONE END OF THE MOLDING REGION TOTHE OTHER OF THE CONTOUR OF THE INTERIOR OF A TUBULAR OBJECT TO BEMOLDED; (H) THE MANDREL HAVING AN INTERNAL CHAMBER; (I) A FLUID SUPPLYMEANS CONNECTED TO THE MANDREL TO SUPPLY FLUID UNDER PRESSURE TO THEMANDREL CHAMBER; AND, (J) MEANS FOR CONTROLLING THE PRESSURE OF THE GASSUPPLIED BY EACH OF SAID SUPPLY MEANS AND THEREBY CONTROL THE DIMENSIONOF AN OBJECT BEING MOLDED.
 3. THE METHOD OF CONTINUOUSLY MOLDING ANELONGATED OBJECT COMPRISING: (A) PROVIDING A QUANTITY OF MOLTENMATERIAL; (B) SHAPING THE MATERIAL INTO AN ELONGATED MEMBER OF CONSTANTCROSS-SECTIONAL CONFIGURATION BY CONTINUOUSLY FEEDING THE MATERIALTHROUGH A MOLDING REGION WITH FORCE APPLIED BY THE MOLTEN MATERIAL ANDTHE REGION DEFINED BY A FORAMINOUS TUBE SHAPED TO THE CONTOUR OF THEOBJECT BEING MOLDED; (C) SOLIDIFYING THE MATERIAL AS IT MOVES THROUGHSAID REGION BY CONFINING THE MATERIAL IN THE REGION UNTIL IT SOLIDIFIESTO ITS FINISHED SHAPE; AND, (D) MAINTAINING A THIN CIRCUMSCRIBING FILMOF MOVING GAS AROUND THE ENTIRE OBJECT BEING MOLDED FROM ONE END OF THEREGION TO THE OTHER BY CONTINUOUSLY PASSING GAS FROM A PLURALITY OFSPACED SOURCES OF GAS UNDER PRESSURE THROUGH THE WALLS OF THE FORAMINOUSTUBE.